Daniel,
Sorry that I haven't provided these logs yet. I'm working on it. There are only limited hours during a maintenance window to reproduce the problem freely.
One thing I can say is that the problem is definitely tied to the 480 Temporarily Unavailable sent from the PBX somehow. If I repoint that DID to my own Asterisk 1.6.x PBX and send some other feedback, OR send a 480 (like Do Not Disturb from a handset), the crash does not present.